DNS servers?? how are they assigned?

Need Help?

That's what we're here for! The goal of the Rogers Community is to help you find answers on everything Rogers. Can't find what you're looking for? Just ask!
cancel
Showing results for 
Search instead for 
Did you mean: 
Reply
baffledalot
I Plan to Stick Around
Posts: 9

DNS servers?? how are they assigned?

Just a question for those who have more expertise than I.

 

I have recently had a situation whereby I was connected to the internet but could not access anything... nothing.

It seems that the problem MAY have been related to my DNS server settings... SO  I wanted to try to understand more about how DNS servers are assigned.

 

1.  how are DNS servers assigned... by the moden?  what about if I have specific settings.. i.e.  in the "Network and Sharing Centre/Change adapter settings/Broadband or Wireless Connection/Properties/Internet Protocol Version 4(TCP/IPv4)/Properties/General tab/Use the following DNS server addresses.

 

IF I do NOT check off "Obtain DNS server automatically".. but rather use the "Use the following DNS server addresses"... What exactly happens?

 

2. What if different machines on a home network have different forced DNS servers?

 

3. Are there other settings in the modem or router that can alter this?

 

Thanks in advance

 

 

 

***Edited Labels***

Solved! Go to Solution.

Accepted Solutions
Datalink
Resident Expert
Resident Expert
Posts: 7,251

Re: DNS servers?? how are they assigned?

1.  If you did nothing to override the modem, it would use the ISP DNS.  The modems usually have a DNS IP address field or two that you can use to specify the DNS that you would prefer to use.  If the field is left empty, the ISP DNS address is used.  If you decide to use another DNS and enter the IP address into the field(s), the entered IP address will be used instead of the ISP DNS.

 

2.  If you run the modem in Gateway mode, using the ISP DNS and then connect another router, or pc, laptop etc to the modem, the ISP DNS will be used unless you override that address in each downstream device.

 

3.  If you run the modem in Gateway mode, with a manually entered DNS address in the modem DNS IP address field, and then connect another router, or pc, laptop etc to the modem, the entered DNS will be used unless you override that address in each downstream device.

 

4.  If you connect a router to the modem, and leave the routers DNS IP address field empty, the router and all devices connected to the router will use the DNS address as supplied by the modem, whether the modem is in Gateway mode or Bridge mode.

 

5.  If you connect a router to the modem, and enter a DNS IP address in the router's DNS address field, the router and all devices connected to the router will use the entered DNS regardless of the ISP address supplied by the modem (ISP or selected address) and regardless of the operating mode of the modem (Gateway mode or Bridge mode).

 

6.  If you enter a DNS IP address in the pc, laptop, etc, it will use that address regardless of what is supplied by the modem or router.  You could in theory, have different DNS IP addresses used by every device that you own, if you took the trouble to enter selected addresses in all of the downstream devices.  That is in fact one way to ensure that you have absolute control over the DNS address.  If your modem was hacked and the DNS field was filled in or changed to redirect the DNS queries to a rogue server, it wouldn't matter as your devices would still use your selected DNS address.  One step further would be to use Open DNS DNSCrypt application, which forces all DNS queries to run encrypted.

 



View solution in original post


All Replies
Datalink
Resident Expert
Resident Expert
Posts: 7,251

Re: DNS servers?? how are they assigned?

1.  If you did nothing to override the modem, it would use the ISP DNS.  The modems usually have a DNS IP address field or two that you can use to specify the DNS that you would prefer to use.  If the field is left empty, the ISP DNS address is used.  If you decide to use another DNS and enter the IP address into the field(s), the entered IP address will be used instead of the ISP DNS.

 

2.  If you run the modem in Gateway mode, using the ISP DNS and then connect another router, or pc, laptop etc to the modem, the ISP DNS will be used unless you override that address in each downstream device.

 

3.  If you run the modem in Gateway mode, with a manually entered DNS address in the modem DNS IP address field, and then connect another router, or pc, laptop etc to the modem, the entered DNS will be used unless you override that address in each downstream device.

 

4.  If you connect a router to the modem, and leave the routers DNS IP address field empty, the router and all devices connected to the router will use the DNS address as supplied by the modem, whether the modem is in Gateway mode or Bridge mode.

 

5.  If you connect a router to the modem, and enter a DNS IP address in the router's DNS address field, the router and all devices connected to the router will use the entered DNS regardless of the ISP address supplied by the modem (ISP or selected address) and regardless of the operating mode of the modem (Gateway mode or Bridge mode).

 

6.  If you enter a DNS IP address in the pc, laptop, etc, it will use that address regardless of what is supplied by the modem or router.  You could in theory, have different DNS IP addresses used by every device that you own, if you took the trouble to enter selected addresses in all of the downstream devices.  That is in fact one way to ensure that you have absolute control over the DNS address.  If your modem was hacked and the DNS field was filled in or changed to redirect the DNS queries to a rogue server, it wouldn't matter as your devices would still use your selected DNS address.  One step further would be to use Open DNS DNSCrypt application, which forces all DNS queries to run encrypted.

 



View solution in original post